The prosecution counsel, Noel Lucas QC, told the court: "The depravity of what was done to the complainants was extreme. The facts of the case will make you uncomfortable. Much of what the girls were forced to endure was perverted in the extreme."

He added: "The evidence will show that these men, sometimes acting in groups and at other times separately, actively targeted vulnerable young girls from the age of about 11 or 12.

"Sometimes the men would come across the girls while the girls were out drinking or playing truant. There is evidence that the men deliberately targeted children who were out of control.

"They also targeted children who had been sent to live in care homes for precisely that reason. Some of the girls had been sexually exploited by other men before they encountered these defendants.

"Sometimes girls already being abused by the group were tasked to find other girls for the group.

"Sometimes the men would also exercise extreme physical and sexual violence on the girls and threaten them that should they ever seek to free themselves from the grasp of the group they and/or their families would suffer serious harm."

Mr Lucas added that the men involved had come from all around England, not just from the Oxford area.

He said: "Many travelled from far afield - places such as Bradford, Leeds, London and Slough. It seems they came specifically to sexually abuse young girls, often by appointment."

The case follows a Thames Valley Police and Oxfordshire County Council investigation into alleged abuse.

The men are all of either Pakistani or north African descent. According to the authorities the youngsters alleged to have been abused are all "vulnerable white British girls".

Thames Valley Police have set up a confidential helpline - 01865 266255 - in response to the investigation that led to the arrests.

The trial is both highly sensitive, because of the nature of the allegations and the links with the Asian community. There have already been small protests by members of the English Defence League.

The trial is expected to last at least eight weeks. The defendants are all in custody.